SQL_触发器

USE [IntertidWebApp]
GO
/****** 对象:  Trigger [dbo].[flt_isexist]    ******/

/*在每次向FLT表插入数据时判断FLT中是否存在相同数据，存在则删除*/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER TRIGGER [dbo].[flt_isexist]
ON [dbo].[FLT]
for INSERT
AS
begin
 declare @id int
 declare @key varchar(10)
 select @id=id,@key=urno from inserted

 IF ((select count(*) from flt where urno = @key)>1)
 begin
  delete from flt where id=@id
  return
 end
end